When Mr Tom Mison arrives at the East London studio, his sharp blue eyes widen at the sight of rails weighed down by cardigans. It just so turns out that the fashion team at MR PORTER has unwittingly chosen to photograph him in his favourite item of clothing and the 29-year-old actor is thrilled at the prospect of getting to wear many of these knits throughout the day.

Why is he so fond of cardigans? "I'm a relaxed person and prefer wearing things that reflect that," he explains. "Cardigans are something you can simply wrap yourself up in - there's something very comforting about that. A big brown cardigan is my idea of perfection. It's what I'd wear while stomping over the heath on my way to find a great pub with an open fire. Cardigans create that romantic image."

A big brown cardigan is my idea of perfection. It's what I'd wear while stomping over the heath on my way to find a great pub with an open fire

That type of aesthetic has served Mr Mison well, as most of his roles have seen him take turns as a posh and lovable Englishman in the vein of Mr Hugh Grant and Mr Colin Firth. He played Mr Bingley in TV series Lost in Austen and garnered critical acclaim on the London theatre scene with a timely performance in Posh. The play saw him depict a young, debauched David Cameron-type figure in a fictionalised version of Oxford University's snobbish Bullingdon Club shortly before the British elections. It was a politically charged happening, and it won him a role in last year's box-office hit One Day.

But does Mr Mison ever feel typecast into playing the English romantic? "Not at all," he says. While he was studying drama at London's Webber-Douglas Academy, a teacher told him, "'Look at yourself, you're not going to get really gritty Ken Loach-style northern council estate parts. Maybe you should look towards the well-spoken period pieces.' Luckily," he continues, "there aren't many men that fit in that role and I'm happy to embrace that. The posher roles I've played have been the most fun."

the work

Oxford's Elite

From left: Mr Mison as James Leighton-Masters and Mr David Dawson as Hugo Fraser-Tyrwhitt in Posh at London's Royal Court Theatre, 2010

A fictitious reality

From left: Mr Mison stars with Ms Alex Kingston as Mr Bingley in Lost in Austen, 2008

a royal performance

From left: Mr David Yelland as King Henry IV and Mr Mison as Prince Hal in Henry IV, Part I, Theatre Royal Bath, 2011

Adding to his portrayals of charmingly traditional British gentlemen is his role in this year's Salmon Fishing in the Yemen, in which he stars alongside a stellar cast that includes Mr Ewan McGregor, Ms Kristin Scott Thomas and the delectable Ms Emily Blunt. The film chronicles the plight of Ms Blunt and Mr McGregor as they try to bring salmon to Yemen to please a local sheik. Mr Mison plays Ms Blunt's boyfriend, a soldier who is thought missing in Afghanistan, and provides much of the non-fishery-based intrigue. "Simon Beaufoy, who wrote Slumdog Millionaire and The Full Monty, adapted it brilliantly," he says excitedly, "and made my role a bit bigger than it was in the book, which is nice."

It's refreshing to hear Mr Mison speak enthusiastically not only about knitwear but about the joys of acting. The hackneyed Method is not for him, he says, adding, "I think the most important thing for an actor is to use your imagination. I think actors often forget to be inventive and surprise people."

As he approaches 30, he plans on overturning his "natural aversion to the gym" and stay in shape for more screen work in America. "There are lots of beautiful actors that make me think, 'I should look a little bit more like that,'" he explains. "But I haven't really felt much pressure... yet." Despite promising projects ahead, Mr Mison maintains, "there still hasn't been a moment where I've felt like, 'wow, I've made it'." But as he slips from portraying a casual character in a navy cardigan thrown over a T-shirt and jeans to looking smart and fashion-forward in a chunky orange knit worn over a denim jacket, Mr Mison seems to have a lot to offer. If his cardigan-wearing skills are anything to go by, we predict that proud moment should come very soon indeed.

Salmon Fishing in the Yemen is out on 9 March in the US, 5 April in Australia and 20 April in the UK

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